Physical modeling, study and optimisation of information supplied by sensors application to flowmeters using tracers

The industrial need accurate flowmeters measures to insure the safety and the performance of their installations. In co-operation with EDF, this study deals with the optimization of the transit time method, for closed cylindrical tubes of nuclear power plants. The method consists in injecting a tracer in the tube then estimating the time necessary for the particles transit between two sections localized below the injection point. In this study the tracer is radioactive and the particles are detected by mean of scintillating probes. A disturbed concentration profile, associated to a weak probes number, leads today to a non accurate estimation. An inverse problem approach is proposed to mitigate these constraints and increase the use of flowmeters using tracers. Simulations using finite difference and Monte Carlo methods allow the calculation of the direct problem. (A.L.B.)